i'm so sorry for your loss. it's very hard to lose a beloved pet. don't blame yourself, she wouldn't want you to. it doesn't mean you did something. sometimes death occurs for no real reason.
She had acites and I have been draining her fluid for a long time. I was giving her a bath as I have done for years, holding her upside down to clean her vent and bad drainage thanks to her disease, and to be sure I did not cause an infection. After I dried her off I put her in my chair and her neck was broken. I don't know what I did. She laid on my lap and died. She thinks I did it on purpose. My heart is broken.
I'm sorry. I don't think you broke her neck. When chickens die, their necks become very limber.
You did so much to care for her and gave her so much love. Please console yourself knowing that she knew she was loved.
I'm sorry you lost Gracie but you didn't cause her death. If you had been draining fluid off her abdomen for that long she had something seriously wrong with her. Ascites in and is itself is not a disease. It's a symptom of a serious issue.
She is now free from whatever was causing her that discomfort.